Cytosolic phospholipase A2-Beta enzymes

ABSTRACT

The invention provides a novel calcium-independent cytosolic phospholipase A 2 -Beta enzyme, polynucleotides encoding such enzyme and methods for screening unknown compounds for anti-inflammatory activity mediated by the arachidonic acid cascade.

This application is a continuation of U.S. Ser. No. 08/788,975 filed on Jan. 24, 1997, abandoned on Dec. 15, 1999.

The present invention relates to a purified cytosolic phospholipase A₂-Beta (cPLA₂-β) enzymes which are useful for assaying chemical agents for anti-inflammatory activity.

BACKGROUND OF THE INVENTION

The phospholipase A₂ enzymes comprise a widely distributed family of enzymes which catalyze the hydrolysis of the acyl ester bond of glycerophospholipids at the sn-2 position. One kind of phospholipase A₂ enzymes, secreted phospholipase A₂ or sPLA₂, are involved in a number of biological functions, including phospholipid digestion, the toxic activities of numerous venoms, and potential antibacterial activities. A second kind of phospholipase A₂ enzymes, the intracellular phospholipase A₂ enzymes, also known as cytosolic phospholipase A₂ or cPLA₂, are active in membrane phospholipid turnover and in regulation of intracellular signalling mediated by the multiple components of the well-known arachidonic acid cascade. One or more cPLA₂ enzymes are believed to be responsible for the rate limiting step in the arachidonic acid cascade, namely, release of arachidonic acid from membrane glycerophospholipids. The action of cPLA₂ also results in biosynthesis of platelet activating factor (PAF). U.S. Pat. Nos. 5,322,776, 5,354,677, 5,527,698 and 5,593,878 disclose such enzymes (sometimes referred to herein as “cPLA₂α”)

The phospholipase B enzymes are a family of enzymes which catalyze the hydrolysis of the acyl ester bond of glycerophospholipids at the sn-1 and sn-2 positions. The mechanism of hydrolysis is unclear but may consist of initial hydrolysis of the sn-2 fatty acid followed by rapid cleavage of the sn-1 substituent, i.e., functionally equivalent to the combination of phospholipase A₂ and lysophospholipase (Saito et al., Methods of Enzymol., 1991, 197, 446; Gassama-Diagne et al., J. Biol. Chem., 1989, 264, 9470). Whether these two events occur at the same or two distinct active sites has not been resolved. It is also unknown if these enzymes have a preference for the removal of unsaturated fatty acids, in particular arachidonic acid, at the sn-2 position and accordingly contribute to the arachidonic acid cascade.

Upon release from the membrane, arachidonic acid may be metabolized via the cyclooxygenase pathway to produce the various prostaglandins and thromboxanes, or via the lipoxygenase pathway to produce the various leukotrienes and related compounds. The prostaglandins, leukotrienes and platelet activating factor are well known mediators of various inflammatory states, and numerous anti-inflammatory drugs have been developed which function by inhibiting one or more steps in the arachidonic acid cascade. The efficacy of the present anti-inflammatory drugs which act through inhibition of arachidonic acid cascade steps is limited by the existence of side effects which may be harmful to various individuals.

A very large industrial effort has been made to identify additional anti-inflammatory drugs which inhibit the arachidonic acid cascade. In general, this industrial effort has employed the secreted phospholipase A₂ enzymes in inhibitor screening assays, for example, as disclosed in U.S. Pat. No. 4,917,826. However, because the secreted phospholipase A₂ enzymes are extracellular proteins (i.e., not cytosolic) and do not selectively hydrolyze arachidonic acid, they are presently not believed to contribute to prostaglandin and leukotriene production. While some inhibitors of the small secreted phospholipase A₂ enzymes have been reported to display anti-inflammatory activity, such as bromphenacyl bromide, mepacrine, and certain butyrophenones as disclosed in U.S. Pat. No. 4,239,780. The site of action of these compounds is unclear as these agents retain anti-inflammatory activity in mouse strains lacking sPLA₂. It is presently believed that inhibitor screening assays should employ cytosolic phospholipase A₂ enzymes which initiate the arachidonic acid cascade.

An improvement in the search for anti-inflammatory drugs which inhibit the arachidonic acid cascade was developed in commonly assigned U.S. Pat. No. 5,322,776, incorporated herein by reference. In that application, a cytosolic form of phospholipase A₂ was identified, isolated, and cloned. Use of the cytosolic form of phospholipase A₂ to screen for anti-inflammatory drugs provides a significant improvement in identifying inhibitors of the arachidonic acid cascade. The cytosolic phospholipase A₂ disclosed in U.S. Pat. No. 5,322,776 is a 110 kD protein which depends on the presence of elevated levels of calcium inside the cell for its activity. The cPLA₂ of U.S. Pat. No. 5,322,776 plays a pivotal role in the production of leukotrienes and prostaglandins initiated by the action of pro-inflammatory cytokines and calcium mobilizing agents. The cPLA₂ of U.S. Pat. No. 5,322,776 is activated by phosphorylation on serine residues and increasing levels of intracellular calcium, resulting in translocation of the enzyme from the cytosol to the membrane where arachidonic acid is selectively hydrolyzed from membrane phospholipids.

In addition to the cPLA₂ of U.S. Pat. No. 5,322,776, some cells contain calcium independent phospholipase A₂/B enzymes. For example, such enzymes have been identified in rat, rabbit, canine and human heart tissue (Gross, TCM, 1991, 2, 115; Zupan et al., J. Med. Chem., 1993, 36, 95; Hazen et al., J. Clin. Invest. 1993, 91, 2513; Lehman et al., J. Biol. Chem., 1993, 268, 20713; Zupan et al., J. Biol. Chem., 1992, 267, 8707; Hazen et al., J. Biol. Chem., 1991, 266, 14526; Loeb et al., J. Biol. Chem., 1986, 261, 10467; Wolf et al., J. Biol. Chem., 1985, 260, 7295; Hazen et al., Meth. Enzymol., 1991, 197, 400; Hazen et al., J. Biol. Chem., 1990, 265, 10622; Hazen et al., J. Biol. Chem., 1993, 268, 9892; Ford et al., J. Clin. Invest., 1991, 88, 331; Hazen et al., J. Biol. Chem., 1991, 266, 5629; Hazen et al., Circulation Res., 1992, 70, 486; Hazen et al., J. Biol. Chem., 1991, 266, 7227; Zupan et al., FEBS, 1991, 284, 27), as well as rat and human pancreatic islet cells (Ramanadham et al., Biochemistry, 1993, 32, 337; Gross et al., Biochemistry, 1993, 32, 327), in the macrophage-like cell line, P388D₁ (Ulevitch et al., J. Biol. Chem., 1988, 263, 3079; Ackermann et al., J. Biol. Chem., 1994, 269, 9227; Ross et al., Arch. Biochem. Biophys., 1985, 238, 247; Ackermann et al., FASEB Journal, 1993, 7(7), 1237), in various rat tissue cytosols (Nijssen et al., Biochim. Biophys. Acta, 1986, 876, 611; Pierik et al., Biochim. Biophys. Acta, 1988, 962, 345; Aarsman et al., J. Biol. Chem., 1989, 264, 10008), bovine brain (Ueda et al., Biochem. Biophys, Res. Comm., 1993, 195, 1272; Hirashima et al., J. Neurochem., 1992, 59, 708), in yeast (Saccharomyces cerevisiae) mitochondria (Yost et al., Biochem. International, 1991, 24, 199), hamster heart cytosol (Cao et al., J. Biol. Chem., 1987, 262, 16027), rabbit lung microsomes (Angle et al., Biochim. Biophys. Acta, 1988, 962, 234) and guinea pig intestinal brush-border membrane (Gassama-Diagne et al., J. Biol. Chem., 1989, 264, 9470). U.S. Pat. Nos. 5,466,595, 5,554,511 and 5,589,170 also disclose calcium independent cPLA₂/B enzymes (sometimes referred to herein as “iPLA₂”).

It is believed that the phospholipase enzymes may perform important functions in release of arachidonic acid in specific tissues which are characterized by unique membrane phospholipids, by generating lysophospholipid species which are deleterious to membrane integrity or by remodeling of unsaturated species of membrane phospholipids through deacylation/reacylation mechanisms. The activity of such a phospholipase may well be regulated by mechanisms that are different from that of the cPLA₂ of U.S. Pat. No. 5,322,776. In addition the activity may be more predominant in certain inflamed tissues over others.

Therefore, it would be desirable to identify and isolate additional cPLA₂ enzymes.

SUMMARY OF THE INVENTION

In other embodiments, the invention provides isolated polynucleotides comprising a nucleotide sequence selected from the group consisting of:

(a) the nucleotide sequence of SEQ ID NO:1;

(b) a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2;

(c) a nucleotide sequence encoding a fragment of the amino acid sequence of SEQ ID NO:2 having activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine;

(d) a nucleotide sequence capable of hybridizing with the sequence of (a), (b) or (c) which encodes a peptide having activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine;

(e) allelic variants of the sequence of (a);

(f) the nucleotide sequence of SEQ ID NO:3;

(g) a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:4;

(h) a nucleotide sequence encoding a fragment of the amino acid sequence of SEQ ID NO:4 having activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine; and

(i) a nucleotide sequence capable of hybridizing with the sequence of (f), (g) or (h) which encodes a peptide having activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine.

Expression vectors comprising such polynucleotides and host cells transformed with such vectors are also provided by the present invention. Compositions comprising peptides encoded by such polynucleotides are also provided.

The present invention also provides processes for producing a phospholipase enzyme, said process comprising: (a) establishing a culture of the host cell transformed with a cPLA₂-Beta encoding polynucleotide in a suitable culture medium; and (b) isolating said enzyme from said culture. Compositions comprising a peptide made according to such processes are also provided.

Certain embodiments of the present invention provide compositions comprising a peptide comprising an amino acid sequence selected from the group consisting of:

(a) the amino acid sequence of SEQ ID NO:2;

(b) a fragment of the amino acid sequence of SEQ ID NO:2 having activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine;

(c) the amino acid sequence of SEQ ID NO:4; and

(d) a fragment of the amino acid sequence of SEQ ID NO:4 having activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine.

The present invention also provides methods for identifying an inhibitor of phospholipase activity, said method comprising: (a) combining a phospholipid, a candidate inhibitor compound, and a composition comprising a phospholipase enzyme peptide; and (b) observing whether said phospholipase enzyme peptide cleaves said phospholipid and releases fatty acid thereby, wherein the peptide composition is one of those described above. Inhibitor of phospholipase activity identified by such methods, pharmaceutical compositions comprising a therapeutically effective amount of such inhibitors and a pharmaceutically acceptable carrier, and methods of reducing inflammation by administering such pharmaceutical compositions to a mammalian subject are also provided.

Polyclonal and monoclonal antibodies to the peptides of the invention are also provided.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A presents data evidenceing increased PLA₂ activity in cells transfected with pEDΔC-n48.

FIG. 1B presents data comparing PLA₂ activities of cells transfected with plasmids expressing cPLA₂α, cPLA₂β and iPLA₂.

FIG. 2 depicts a gel evidencing the expression of cPLA₂β in COS cells.

DETAILED DESCRIPTION OF THE INVENTION

A cDNA encoding the cPLA₂-Beta of the present invention was isolated as described in Example 1. The sequence of the partial cDNA first isolated is reported as SEQ ID NO:1. The amino acid sequence encoded by such cDNA is SEQ ID NO:2. For purposes of expression, as explained in Example 1, polynucleotides encoding N-terminal sequence from cPLA₂ was added to the partial cDNA. The polynucleotide sequence of this fusion is reported as SEQ ID NO:3. The amino acid sequence encoded by the fuion cDNA is reported as SEQ ID NO:4.

The invention also encompasses allelic variations of the cDNA sequence as set forth in SEQ ID NO:1 and SEQ ID NO:3, that is, naturally-occurring alternative forms of the cDNAs of SEQ ID NO:1 and SEQ ID NO:3 which also encode phospholipase enzymes of the present invention. Also included in the invention are isolated DNAs which hybridize to the DNA sequence set forth in SEQ ID NO:1 or SEQ ID NO:3 under stringent (e.g. 4×SSC at 65° C. or 50% formamide and 4×SSC at 42° C.), or relaxed (4×SSC at 50° C. or 30-40% formamide at 42° C.) conditions.

The isolated polynucleotides of the invention may be operably linked to an expression control sequence such as the pMT2 or pED expression vectors disclosed in Kaufman et al., Nucleic Acids Res. 19, 4485-4490 (1991), in order to produce the phospholipase enzyme peptides recombinantly. Many suitable expression control sequences are known in the art. General methods of expressing recombinant proteins are also known and are exemplified in R. Kaufman, Methods in Enzymology 185, 537-566 (1990). As defined herein “operably linked” means enzymatically or chemically ligated to form a covalent bond between the isolated polynucleotide of the invention and the expression control sequence, in such a way that the phospholipase enzyme peptide is expressed by a host cell which has been transformed (transfected) with the ligated polynucleotide/expression control sequence.

A number of types of cells may act as suitable host cells for expression of the phospholipase enzyme peptide. Suitable host cells are capable of attaching carbohydrate side chains characteristic of functional phospholipase enzyme peptide. Such capability may arise by virtue of the presence of a suitable glycosylating enzyme within the host cell, whether naturally occurring, induced by chemical mutagenesis, or through transfection of the host cell with a suitable expression plasmid containing a polynucleotide encoding the glycosylating enzyme. Host cells include, for example, monkey COS cells, Chinese Hamster Ovary (CHO) cells, human kidney 293 cells, human epidermal A431 cells, human Colo205 cells, 3T3 cells, CV-1 cells, other transformed primate cell lines, normal diploid cells, cell strains derived from in vitro culture of primary tissue, primary explants, HeLa cells, mouse L cells, BHK, HL-60, U937, or HaK cells.

The phospholipase enzyme peptide may also be produced by operably linking the isolated polynucleotide of the invention to suitable control sequences in one or more insect expression vectors, and employing an insect expression system. Materials and methods for baculovirus/insect cell expression systems are commercially available in kit form from, e.g., Invitrogen, San Diego, Calif., U.S.A. (the MaxBac® kit), and such methods are well known in the art, as described in Summers and Smith, Texas Agricultural Experiment Station Bulletin No. 1555 (1987), incorporated herein by reference.

Alternatively, it may be possible to produce the phospholipase enzyme peptide in lower eukaryotes such as yeast or in prokaryotes such as bacteria. Potentially suitable yeast strains include Saccharomyces cerevisiae, Schizosaccharomycespombe, Kluyveromyces strains, Candida, or any yeast strain capable of expressing heterologous proteins. Potentially suitable bacterial strains include Escherichia coli, Bacillus subtilis, Salmonella typhimurium, or any bacterial strain capable of expressing heterologous proteins. If the phospholipase enzyme peptide is made in yeast or bacteria, it is necessary to attach the appropriate carbohydrates to the appropriate sites on the protein moiety covalently, in order to obtain the glycosylated phospholipase enzyme peptide. Such covalent attachments may be accomplished using known chemical or enzymatic methods.

The phospholipase enzyme peptide of the invention may also be expressed as a product of transgenic animals, e.g., as a component of the milk of transgenic cows, goats, pigs, or sheep which are characterized by somatic or germ cells containing a polynucleotide encoding the phospholipase enzyme peptide.

The phospholipase enzyme peptide of the invention may be prepared by culturing transformed host cells under culture conditions necessary to express a phospholipase enzyme peptide of the present invention. The resulting expressed protein may then be purified from culture medium or cell extracts as described in the examples below.

Alternatively, the phospholipase enzyme peptide of the invention is concentrated using a commercially available protein concentration filter, for example, an Amicon or Millipore Pellicon ultrafiltration unit. Following the concentration step, the concentrate can be applied to a purification matrix such as a gel filtration medium. Alternatively, an anion exchange resin can be employed, for example, a matrix or substrate having pendant diethylaminoethyl (DEAE) groups. The matrices can be acrylamide, agarose, dextran, cellulose or other types commonly employed in protein purification. Alternatively, a cation exchange step can be employed. Suitable cation exchangers include various insoluble matrices comprising sulfopropyl or carboxymethyl groups. Sulfopropyl groups are preferred (e.g., S-Sepharose® columns). The purification of the phospholipase enzyme peptide from culture supernatant may also include one or more column steps over such affinity resins as concanavalin A-agarose, heparin-toyopearl® or Cibacrom blue 3GA Sepharose®; or by hydrophobic interaction chromatography using such resins as phenyl ether, butyl ether, or propyl ether; or by immunoaffinity chromatography.

Finally, one or more reverse-phase high performance liquid chromatography (RP-HPLC) steps employing hydrophobic RP-HPLC media, e.g., silica gel having pendant methyl or other aliphatic groups, can be employed to further purify the phospholipase enzyme peptide. Some or all of the foregoing purification steps, in various combinations, can also be employed to provide a substantially homogeneous isolated recombinant protein. The phospholipase enzyme peptide thus purified is substantially free of other mammalian proteins and is defined in accordance with the present invention as “isolated phospholipase enzyme peptide”.

The cPLA₂-Beta of the present invention may be used to screen for compounds having anti-inflammatory activity mediated by the various components of the arachidonic acid cascade. Many assays for phospholipase activity are known and may be used with the phospholipase A₂-Beta on the present invention to screen unknown compounds. For example, such an assay may be a mixed micelle assay as described in Example 2. Other known phospholipase activity assays include, without limitation, those disclosed in U.S. Pat. No. 5,322,776. These assays may be performed manually or may be automated or robotized for faster screening. Methods of automation and robotization are known to those skilled in the art.

In one possible screening assay, a first mixture is formed by combining a phospholipase enzyme peptide of the present invention with a phospholipid cleavable by such peptide, and the amount of hydrolysis in the first mixture (B₀) is measured. A second mixture is also formed by combining the peptide, the phospholipid and the compound or agent to be screened, and the amount of hydrolysis in the second mixture (B) is measured. The amounts of hydrolysis in the first and second mixtures are compared, for example, by performing a B/B₀. calculation. A compound or agent is considered to be capable of inhibiting phospholipase activity (i.e., providing anti-inflammatory activity) if a decrease in hydrolysis in the second mixture as compared to the first mixture is observed. The formulation and optimization of mixtures is within the level of skill in the art, such mixtures may also contain buffers and salts necessary to enhance or to optimize the assay, and additional control assays may be included in the screening assay of the invention.

Other uses for the cPLA₂-Beta of the present invention are in the development of monoclonal and polyclonal antibodies. Such antibodies may be generated by employing purified forms of the cPLA₂ or immunogenic fragments thereof as an antigen using standard methods for the development of polyclonal and monoclonal antibodies as are known to those skilled in the art. Such polyclonal or monoclonal antibodies are useful as research or diagnostic tools, and further may be used to study phospholipase A₂ activity and inflammatory conditions.

Pharmaceutical compositions containing anti-inflammatory agents (i.e., inhibitors) identified by the screening method of the present invention may be employed to treat, for example, a number of inflammatory conditions such as rheumatoid arthritis, psoriasis, asthma, inflammatory bowel disease and other diseases mediated by increased levels of prostaglandins, leukotriene, or platelet activating factor. Pharmaceutical compositions of the invention comprise a therapeutically effective amount of a cPLA₂ inhibitor compound first identified according to the present invention in a mixture with an optional pharmaceutically acceptable carrier. The term “pharmaceutically acceptable” means a non-toxic material that does not interfere with the effectiveness of the biological activity of the active ingredient(s). The term “therapeutically effective amount” means the total amount of each active component of the method or composition that is sufficient to show a meaningful patient benefit, i.e., healing or amelioration of chronic conditions or increase in rate of healing or amelioration. When applied to an individual active ingredient, administered alone, the term refers to that ingredient alone. When applied to a combination, the term refers to combined amounts of the active ingredients that result in the therapeutic effect, whether administered in combination, serially or simultaneously. A therapeutically effective dose of the inhibitor of this invention is contemplated to be in the range of about 0.1 μg to about 100 mg per kg body weight per application. It is contemplated that the duration of each application of the inhibitor will be in the range of 12 to 24 hours of continuous administration. The characteristics of the carrier or other material will depend on the route of administration.

The amount of inhibitor in the pharmaceutical composition of the present invention will depend upon the nature and severity of the condition being treated, and on the nature of prior treatments which the patient has undergone. Ultimately, the attending physician will decide the amount of inhibitor with which to treat each individual patient. Initially, the attending physician will administer low doses of inhibitor and observe the patient's response. Larger doses of inhibitor may be administered until the optimal therapeutic effect is obtained for the patient, and at that point the dosage is not increased further.

Administration is preferably intravenous, but other known methods of administration for anti-inflammatory agents may be used. Administration of the anti-inflammatory compounds identified by the method of the invention can be carried out in a variety of conventional ways. For example, for topical administration, the anti-inflammatory compound of the invention will be in the form of a pyrogen-free, dermatologically acceptable liquid or semi-solid formulation such as an ointment, cream, lotion, foam or gel. The preparation of such topically applied formulations is within the skill in the art. Gel formulation should contain, in addition to the anti-inflammatory compound, about 2 to about 5% W/W of a gelling agent. The gelling agent may also function to stabilize the active ingredient and preferably should be water soluble. The formulation should also contain about 2% W/V of a bactericidal agent and a buffering agent. Exemplary gels include ethyl, methyl, and propyl celluloses. Preferred gels include carboxypolymethylene such as Carbopol (934P; B.F. Goodrich), hydroxypropyl methylcellulose phthalates such as Methocel (K100M premium; Merril Dow), cellulose gums such as Blanose (7HF; Aqualon, U.K.), xanthan gums such as Keltrol (TF; Kelko International), hydroxyethyl cellulose oxides such as Polyox (WSR 303; Union Carbide), propylene glycols, polyethylene glycols and mixtures thereof. If Carbopol is used, a neutralizing agent, such as NaOH, is also required in order to maintain pH in the desired range of about 7 to about 8 and most desirably at about 7.5. Exemplary preferred bactericidal agents include steryl alcohols, especially benzyl alcohol. The buffering agent can be any of those already known in the art as useful in preparing medicinal formulations, for example 20 mM phosphate buffer, pH 7.5.

Cutaneous or subcutaneous injection may also be employed and in that case the anti-inflammatory compound of the invention will be in the form of pyrogen-free, parenterally acceptable aqueous solutions. The preparation of such parenterally acceptable solutions, having due regard to pH, isotonicity, stability, and the like, is within the skill in the art.

Intravenous injection may be employed, wherein the anti-inflammatory compound of the invention will be in the form of pyrogen-free, parenterally acceptable aqueous solutions. A preferred pharmaceutical composition for intravenous injection should contain, in addition to the anti-inflammatory compound, an isotonic vehicle such as Sodium Chloride Injection. Ringer's Injection, Dextrose Injection, Dextrose and Sodium Chloride Injection, Lactated Ringer's Injection, or other vehicle as known in the art. The pharmaceutical composition according to the present invention may also contain stabilizers, preservatives, buffers, antioxidants, or other additive known to those of skill in the art.

The amount of anti-inflammatory compound in the pharmaceutical composition of the present invention will depend upon the nature and severity of the condition being treated, and on the nature of prior treatments which the patient has undergone. Ultimately, the attending physician will decide the amount of anti-inflammatory compound with which to treat each individual patient.

Anti-inflammatory compounds identified using the method of the present invention may be administered alone or in combination with other anti-inflammation agents and therapies.

Example 1

Library Construction

Oligo-dT primed and random primed cDNA libraries were constructed from U937 cells using a Poly ATrack kit for isolation of mRNA (Promega), a Superscript Choice kit for the generation of double stranded cDNA (Gibco BRL), and a Lambda ZapII phage cloning kit (Stratagene).

Clone Identification

Two cPLA₂-β specific deoxyribonucleotides were designed based on the sequence of EST clone W92213:

5′-CCTCCTGCAGCCCACTCGGGAC-3′ (SEQ ID NO:5)

5′-GCTGACCAGAGGAAAGTGCAGC-3′ (SEQ ID NO:6)

These oligonucleotides were used to screen 10⁶ recombinates of both the oligo dT primed and random primed library. One clone which hybridizes with both oligonucleotides, clone 52A, was examined for complete DNA sequence determination (SEQ ID NO:1). The partial coding sequence on this clone begins at nucleotide 1560 and continues to a stop codon at nucleotide 3894, representing 778 amino acids (see SEQ ID NO:2). The region on the DNA sequence 5′ to nucleotide 1560 fits a splice acceptor consensus sequence and is therefore assumed to be unspliced intron sequence.

A comparison of the previous cPLA₂ amino acid sequence with the predicted cPLA₂-β sequence reveals 30% overall identity. It also predicts this clone to be lacking only 11 amino acids from the N-terminus. For this reason we decided to make a chimeric construct using the first 11 amino acids of cPLA₂ fused to the 778 amino acids of cPLA₂-β. This construct can be used to confirm the activity of the cPLA₂-β protein.

Construction of Expression Vectors to Produce cPLA2β Protein in COS-7 Cells:

An adapter was generated using synthesized oligonucleotides. Its sequence and encoded amino acids are shown below.

    CTAGAGAATTCACCACCATGGACTACAAGGACGACGATGACAAGTCATTTATAGATCCTT (SEQ ID NO:7)   1     ---------+---------+---------+---------+---------+---------+60         TCTTAAGTGGTGGTACCTGATGTTCCTGCTGCTACTGTTCAGTAAATATCTAGGAA (SEQ ID NO:8)                      M  D  Y  K  D  D  D  D  K  S  F  I  D  P Y - (SEQ ID NO:9)                       Flag-Tag                  cPLA2  linker ACCAGCACATTATAGCAGAGGTGTCCAGGACCTGCCTGCTCACGGTTCGTGTCCTGCAGG  61 ---------+---------+---------+---------+---------+---------+120 TGGTCGTGTAATATCGTCTCCACAGGTCCTGGACGGACGAGTGCCAAGCACAGGACGTCC   O  H  I  I  A  E  V  S  R  T  C  L  L  T  V  R  V  L  O  A -                 {circumflex over ( )}cPLA2 starts here CCCATCGCCTACCCTCTAAGGACC 121 ---------+---------+----144 GGGTAGCGGATGGGAGATTCCTGGAT H  R  L  P  S  K  D 

This adapter was ligated with the largest BfaI-EcoRI fragment from clone 52A (bps 1630-4183) into EcoRI/XbaI digested pEDΔC vector. The resulted clone, named pEDΔC-n48, was confirmed to contain the desired inserts by restriction enzyme digestion and DNA sequencing. The sequence of the resulted clone is reported as SEQ ID NO:3.

Clone 52A was deposited with the American Type Culture Collection on Jan. 23, 1997 as accession number 98301. pEDΔC-n48 was deposited with the American Type Culture Collection on Jan. 22, 1997 as accession number 98302.

(2) Transfection and Activity Assay:

Eight micrograms of plasmid pEDΔC-n48 was transfected into COS-7 cells on 10 cm cell culture plate using lipofectamine (GIBCO BRL) according to manufacturer's protocol. PEDΔC vector DNA, pEMC-cPLA2, pEMCiPLA2 were also transfected in parallel experiments. At 66 hours posttransfection, cells were washed twice with 10 ml of ice-cold TBS, scraped into 1 ml of TBS. Cell pellets were collected, resuspended in lysis buffer (10 mM HEPES, pH 7.5, 1 mM EDTA, 0.1 mM DTT, 0.34 M sucrose, 1 mM PMSF and 1 ug/ml leupeptin) and lysed in a Parr-bomb (700 psi, 10 min) on ice. The lysate were centrifuged at 100,000 g for 1 hr at 4° C. The supernatant (cytosolic fraction) was transferred to another set of tubes and the pellets were resuspended in 0.5 volume of lysis buffer (particulate fraction). Twenty ul of the lysate or cytosolic fraction or 10 ul of the particulate fraction were mixed on ice with 100 ul substrate containing 20 uM 1-palmitoyl-2-[1-14C]-arachidonyl-L-3-Phosphotidylcholine, 80 mM glycine, pH 9.0, 200 uM Triton-X 100, 70% glycerol and 10 mM CaCl2. The reaction was carried out at 37° C. for 15 min and the products analyzed as described (PNAS 87, pp7708-7712, 1990).

Example 2 Phopholipase Assays

1. sn-2 Hydrolysis Assays

A) Liposome:

The lipid, e.g. 1-palmitoyl-2-[¹⁴C]arachidonyl-sn-glycero-3-phosphocholine(PAPC), 55 mCi/mmol, was dried under a stream of nitrogen and solubilized in ethanol. The assay buffer contained 100 mM Tris-HCl pH 7, 4 mM EDTA, 4 mM EGTA, 10% glycerol and 25 μM of labelled PAPC, where the volume of ethanol added was no more than 10% of the final assay volume. The reaction was incubated for 30 minutes at 37° C. and quenched by the addition of two volumes of heptane:isopropanol: 0.5M sulfuric acid (105:20:1 v/v). Half of the organic was applied to a disposable silica gel column in a vacuum manifold positioned over a scintillation vial, and the free arachidonic was eluted by the addition of ethyl ether (1 ml). The level of radioactivity was measured by liquid scintillation.

Variations on this assay replace EDTA and EGTA with 10 mM CaCl₂.

B) Mixed Micelle Basic:

The lipid was dried down as in (A) and to this was added the assay buffer consisting of 80 mM glycine pH 9, 5 mM CaCl₂ or 5 mM EDTA, 10% or 70% glycerol and 200 μM triton X-100. The mixture was then sonicated for 30-60 seconds at 4° C. to form mixed micelles.

C) Mixed Micelle Neutral:

As for (B) except 100 mM Tris-HCl pH 7 was used instead of glycine as the buffer.

2. sn-1 Hydrolysis Assays

Sn-1 hydrolysis assays are performed as described above for sn-1 hydrolysis, but using phospholipids labelled at the sn-1 substituent, e.g. 1-[¹⁴C]-palmitoyl-2-arachidonyl-sn-glycero-3-phophocholine.

Patent and literature references cited herein are incorporated by reference as if fully set forth.

9 4183 base pairs nucleic acid double linear cDNA not provided 1 CTCCTACAAC TCAATATAAA AACATAAACC CAGCCGGGTG CAGTGGCTCA TGCCTGTAAT 60 CCCAACACTT TGGAAAGGCC AAGGTGGGTG GATCACCTGA GGTCAGGAGT TCAAGACCAG 120 CCTGGCCAAC ATGGTAAGAC CCGTCTCTAC TAAAAATACA AAAATTAGCC AGTGTAGTGG 180 TGGGCACCTG TAATCCAGCT ACTCAGGAGG CTGGGGCAGG AGAATCACTT GAACCTGGGA 240 GGCGGAGGTT GCAGTGAGCC GAGATTGCAC CATTGCACTC CTGCTTGGGT GACAGAGCGA 300 GACTCCATCT CAAAAAAAAA AAAGATAAAC CCAATTTTAA AATGGGCAAA AGACCTGAAT 360 AGGCAAACCT CCAAAGAAAA TATGTGCATG AAAAGATGCT TAACATCATT TGTCATCAAA 420 TGGTTAGGAA ATTGCAAATC AAAACCACAG TGAGATACCT CTTCAAACTT ACTAGGATGG 480 CTATAATCAA AAAGATAAAC AACAACAAGT ATTAGAGATG ATGTGGAGAA ACTAGAACCC 540 TCATATATGC TGGTGGGAAT GTAAAATGGT GCAGCCACTT TGGAAAACTG TCTGGCATTT 600 CTTCAAAAAG TAACATAGAG TTACTGTATG ACCCAGCAAT TCCACTGCTA GTGTGTATCC 660 AAGAGAAATG AAAACGTGTC CACACAAAAA GTTGGACACA AATGTTCACG GCAGCATTGT 720 TTATAATAGC CAAAAAATAG AAACACCCAA ATGTCCATCA ACTGATTTAA TGAGTAAAGA 780 TAATGAGATA TGTCTATACA ATAGATTATT ATTTGGCAAT AAAAAGGAAT AAAGTTCTGG 840 TTGGGCATGG TGGCTCACAC CTGTAATCCC AGCACTTTGA GAGGCTGAGG TGGGAAGACT 900 GCTTAAGCCA GAAGTTCAAG ACCAGCCCAG ACAACAAAGC AAGACCTTAT CTCTACAGAC 960 TTTCTAAAAA TTAGCCAGGT GTGGCTGGGT GTGGTGGCTC ACGCCTGTAG TCCCAGCACA 1020 TTGGGAGGCA TAGGCGGGCG GATCACGAGG TCAGGAGATG GAGACCATCC TGGTTAACAC 1080 GGCGAAACCC CGTCTCTACT AAAAATACAA AAAATTAGCT GGGCGTGGTG GCGGGCGCCT 1140 GTAGTCCCAG CTACTCGGGA AGCCGAGGCA GGAGAATGGC GTGAACCTGG GAGGTGGAGC 1200 TCGCAGTGAG CCGAGATCGC GCCACTGCAC TCCAGCCTGG GGGACAGAGT GAGACTCCCA 1260 TCCCAAAGAA AAAAAAAATT AGCCGGGTGT GGTGGTACAT GCCAGTAGTC CCAGCTACCT 1320 GGGAGGCCAA GGCAGGAGGA CTGCTTGAAT CCAGGAAGTT GAGGCTGCAG TGAGCGATGA 1380 TGGCACCACT GCACTTCAAC CTAGACAAGG TCGACGCGGC CNNGAATTAG CGNCCGCGTC 1440 GANNGATGGG CCTGGGGTTC AGGATTAGGC CTTGAGGCAC TGCTCCAGCC TCCTTTGTGG 1500 CCCCTGTCAC CCTTGGCTTC ATCGGCCCGT AGCAGGTCTC CCCTCTCCCA CCTCTGCAGG 1560 CAGAGGTGTC CAGGACCTGC CTGCTCACGG TTCGTGTCCT GCAGGCCCAT CGCCTACCCT 1620 CTAAGGACCT AGTGACCCCC TCTGACTGCT ACGTGACTCT CTGGCTGCCC ACGGCCTGCA 1680 GCCACAGGCT CCAGACACGC ACGGTCAAGA ACAGCAGTAG CCCTGTCTGG AACCAGAGCT 1740 TTCACTTCAG GATCCACAGG CAGCTCAAGA ATGTCATGGA ACTGAAAGTC TTTGACCAGG 1800 ACCTGGTGAC CGGAGATGAC CCTGTGTTGT CAGTACTGTT TGATGCGGGG ACTCTGCGGG 1860 CTGGGGAGTT CCGGCGCGAG AGCTTCTCAC TGAGCCCTCA GGGTGAGGGG CGCCTGGAAG 1920 TTGAATTTCG CCTGCAGAGT CTGGCTGACC GTGGCGAGTG GCTCGTCAGC AATGGCGTTC 1980 TGGTGGCCCG GGAGCTCTCC TGCTTGCACG TTCAACTGGA GGAGACAGGA GACCAGAAGT 2040 CCTCAGAGCA CAGAGTTCAG CTTGTGGTTC CTGGGTCCTG TGAGGGTCCG CAGGAGGCCT 2100 CTGTGGGCAC TGGCACCTTC CGCTTCCACT GCCCAGCCTG CTGGGAGCAG GAGCTGAGTA 2160 TTCGCCTGCA GGATGCCCCC GAGGAGCAAC TAAAGGCGCC ACTGAGTGCC CTGCCCTCTG 2220 GTCAAGTGGT GAGGCTTGTC TTCCCCACGT CCCAGGAGCC CCTGATGAGA GTGGAGCTGA 2280 AAAAAGAAGC AGGACTGAGG GAGCTGGCCG TGCGACTGGG CTTCGGGCCC TGTGCAGAGG 2340 AGCAGGCCTT CCTGAGCAGG AGGAAGCAGG TGGTGGCCGC GGCCTTGAGG CAGGCCCTGC 2400 AGCTGGATGG AGACCTGCAG GAGGATGAGA TCCCAGTGGT AGCTATTATG GCCACTGGTG 2460 GTGGGATCCG GGCAATGACT TCCCTGTATG GGCAGCTGGC TGGCCTGAAG GAGCTGGGCC 2520 TCTTGGATTG CGTCTCCTAC ATCACCGGGG CCTCGGGCTC CACCTGGGCC TTGGCCAACC 2580 TTTATGAGGA CCCAGAGTGG TCTCAGAAGG ACCTGGCAGG GCCCACTGAG TTGCTGAAGA 2640 CCCAGGTGAC CAAGAACAAG CTGGGTGTGC TGGCCCCCAG CCAGCTGCAG CGGTACCGGC 2700 AGGAGCTGGC CGAGCGTGCC CGCTTGGGCT ACCCAAGCTG CTTCACCAAC CTGTGGGCCC 2760 TCATCAACGA GGCGCTGCTG CATGATGAGC CCCATGATCA CAAGCTCTCA GATCAACGGG 2820 AGGCCCTGAG TCATGGCCAG AACCCTCTGC CCATCTACTG TGCCCTCAAC ACCAAAGGGC 2880 AGAGCCTGAC CACTTTTGAA TTTGGGGAGT GGTGCGAGTT CTCTCCCTAC GAGGTCGGCT 2940 TCCCCAAGTA CGGGGCCTTC ATCCCCTCTG AGCTCTTTGG CTCCGAGTTC TTTATGGGGC 3000 AGCTGATGAA GAGGCTTCCT GAGTCCCGCA TCTGCTTCTT AGAAGGTATC TGGAGCAACC 3060 TGTATGCAGC CAACCTCCAG GACAGCTTAT ACTGGGCCTC AGAGCCCAGC CAGTTCTGGG 3120 ACCGCTGGGT CAGGAACCAG GCCAACCTGG ACAAGGAGCA GGTCCCCCTT CTGAAGATAG 3180 AAGAACCACC CTCAACAGCC GGCAGGATAG CTGAGTTTTT CACCGATCTT CTGACGTGGC 3240 GTCCACTGGC CCAGGCCACA CATAATTTCC TGCGTGGCCT CCATTTCCAC AAAGACTACT 3300 TTCAGCATCC TCACTTCTCC ACATGGAAAG CTACCACTCT GGATGGGCTC CCCAACCAGC 3360 TGACACCCTC GGAGCCCCAC CTGTGCCTGC TGGATGTTGG CTACCTCATC AATACCAGCT 3420 GCCTGCCCCT CCTGCAGCCC ACTCGGGACG TGGACCTCAT CCTGTCATTG GACTACAACC 3480 TCCACGGAGC CTTCCAGCAG TTGCAGCTCC TGGGCCGGTT CTGCCAGGAG CAGGGGATCC 3540 CGTTCCCACC CATCTCGCCC AGCCCCGAAG AGCAGCTCCA GCCTCGGGAG TGCCACACCT 3600 TCTCCGACCC CACCTGCCCC GGAGCCCCTG CGGTGCTGCA CTTTCCTCTG GTCAGCGACT 3660 CCTTCCGGGA GTACTCGGCC CCTGGGGTCC GGCGGACACC CGAGGAGGCG GCAGCTGGGG 3720 AGGTGAACCT GTCTTCATCG GACTCTCCCT ACCACTACAC GAAGGTGACC TACAGCCAGG 3780 AGGACGTGGA CAAGCTGCTG CACCTGACAC ATTACAATGT CTGCAACAAC CAGGAGCAGC 3840 TGCTGGAGGC TCTGCGCCAG GCAGTGCAGC GGAGGCGGCA GCGCAGGCCC CACTGATGGC 3900 CGGGGCCCCT GCCACCCCTA ACTCTCATTC ATTCCCTGGC TGCTGAGTTG CAGGTGGGAA 3960 CTGTCATCAC GCAGTGCTTC AGAGCCTCGG GCTCAGGTGG CACTGTCCCA GGGTCCAGGC 4020 TGAGGGCTGG GAGCTCCCTT GCGCCTCAGC AGTTTGCAGT GGGGTAAGGA GGCCAAGCCC 4080 ATTTGTGTAA TCACCCAAAA CCCCCCGGCC TGTGCCTGTT TTCCCTTCTG CGCTACCTTG 4140 AGTAGTTGGA GCACTTGATA CATCACAGAC TCATACAAAT GTG 4183 778 amino acids amino acid linear protein not provided 2 Ala Glu Val Ser Arg Thr Cys Leu Leu Thr Val Arg Val Leu Gln Ala 1 5 10 15 His Arg Leu Pro Ser Lys Asp Leu Val Thr Pro Ser Asp Cys Tyr Val 20 25 30 Thr Leu Trp Leu Pro Thr Ala Cys Ser His Arg Leu Gln Thr Arg Thr 35 40 45 Val Lys Asn Ser Ser Ser Pro Val Trp Asn Gln Ser Phe His Phe Arg 50 55 60 Ile His Arg Gln Leu Lys Asn Val Met Glu Leu Lys Val Phe Asp Gln 65 70 75 80 Asp Leu Val Thr Gly Asp Asp Pro Val Leu Ser Val Leu Phe Asp Ala 85 90 95 Gly Thr Leu Arg Ala Gly Glu Phe Arg Arg Glu Ser Phe Ser Leu Ser 100 105 110 Pro Gln Gly Glu Gly Arg Leu Glu Val Glu Phe Arg Leu Gln Ser Leu 115 120 125 Ala Asp Arg Gly Glu Trp Leu Val Ser Asn Gly Val Leu Val Ala Arg 130 135 140 Glu Leu Ser Cys Leu His Val Gln Leu Glu Glu Thr Gly Asp Gln Lys 145 150 155 160 Ser Ser Glu His Arg Val Gln Leu Val Val Pro Gly Ser Cys Glu Gly 165 170 175 Pro Gln Glu Ala Ser Val Gly Thr Gly Thr Phe Arg Phe His Cys Pro 180 185 190 Ala Cys Trp Glu Gln Glu Leu Ser Ile Arg Leu Gln Asp Ala Pro Glu 195 200 205 Glu Gln Leu Lys Ala Pro Leu Ser Ala Leu Pro Ser Gly Gln Val Val 210 215 220 Arg Leu Val Phe Pro Thr Ser Gln Glu Pro Leu Met Arg Val Glu Leu 225 230 235 240 Lys Lys Glu Ala Gly Leu Arg Glu Leu Ala Val Arg Leu Gly Phe Gly 245 250 255 Pro Cys Ala Glu Glu Gln Ala Phe Leu Ser Arg Arg Lys Gln Val Val 260 265 270 Ala Ala Ala Leu Arg Gln Ala Leu Gln Leu Asp Gly Asp Leu Gln Glu 275 280 285 Asp Glu Ile Pro Val Val Ala Ile Met Ala Thr Gly Gly Gly Ile Arg 290 295 300 Ala Met Thr Ser Leu Tyr Gly Gln Leu Ala Gly Leu Lys Glu Leu Gly 305 310 315 320 Leu Leu Asp Cys Val Ser Tyr Ile Thr Gly Ala Ser Gly Ser Thr Trp 325 330 335 Ala Leu Ala Asn Leu Tyr Glu Asp Pro Glu Trp Ser Gln Lys Asp Leu 340 345 350 Ala Gly Pro Thr Glu Leu Leu Lys Thr Gln Val Thr Lys Asn Lys Leu 355 360 365 Gly Val Leu Ala Pro Ser Gln Leu Gln Arg Tyr Arg Gln Glu Leu Ala 370 375 380 Glu Arg Ala Arg Leu Gly Tyr Pro Ser Cys Phe Thr Asn Leu Trp Ala 385 390 395 400 Leu Ile Asn Glu Ala Leu Leu His Asp Glu Pro His Asp His Lys Leu 405 410 415 Ser Asp Gln Arg Glu Ala Leu Ser His Gly Gln Asn Pro Leu Pro Ile 420 425 430 Tyr Cys Ala Leu Asn Thr Lys Gly Gln Ser Leu Thr Thr Phe Glu Phe 435 440 445 Gly Glu Trp Cys Glu Phe Ser Pro Tyr Glu Val Gly Phe Pro Lys Tyr 450 455 460 Gly Ala Phe Ile Pro Ser Glu Leu Phe Gly Ser Glu Phe Phe Met Gly 465 470 475 480 Gln Leu Met Lys Arg Leu Pro Glu Ser Arg Ile Cys Phe Leu Glu Gly 485 490 495 Ile Trp Ser Asn Leu Tyr Ala Ala Asn Leu Gln Asp Ser Leu Tyr Trp 500 505 510 Ala Ser Glu Pro Ser Gln Phe Trp Asp Arg Trp Val Arg Asn Gln Ala 515 520 525 Asn Leu Asp Lys Glu Gln Val Pro Leu Leu Lys Ile Glu Glu Pro Pro 530 535 540 Ser Thr Ala Gly Arg Ile Ala Glu Phe Phe Thr Asp Leu Leu Thr Trp 545 550 555 560 Arg Pro Leu Ala Gln Ala Thr His Asn Phe Leu Arg Gly Leu His Phe 565 570 575 His Lys Asp Tyr Phe Gln His Pro His Phe Ser Thr Trp Lys Ala Thr 580 585 590 Thr Leu Asp Gly Leu Pro Asn Gln Leu Thr Pro Ser Glu Pro His Leu 595 600 605 Cys Leu Leu Asp Val Gly Tyr Leu Ile Asn Thr Ser Cys Leu Pro Leu 610 615 620 Leu Gln Pro Thr Arg Asp Val Asp Leu Ile Leu Ser Leu Asp Tyr Asn 625 630 635 640 Leu His Gly Ala Phe Gln Gln Leu Gln Leu Leu Gly Arg Phe Cys Gln 645 650 655 Glu Gln Gly Ile Pro Phe Pro Pro Ile Ser Pro Ser Pro Glu Glu Gln 660 665 670 Leu Gln Pro Arg Glu Cys His Thr Phe Ser Asp Pro Thr Cys Pro Gly 675 680 685 Ala Pro Ala Val Leu His Phe Pro Leu Val Ser Asp Ser Phe Arg Glu 690 695 700 Tyr Ser Ala Pro Gly Val Arg Arg Thr Pro Glu Glu Ala Ala Ala Gly 705 710 715 720 Glu Val Asn Leu Ser Ser Ser Asp Ser Pro Tyr His Tyr Thr Lys Val 725 730 735 Thr Tyr Ser Gln Glu Asp Val Asp Lys Leu Leu His Leu Thr His Tyr 740 745 750 Asn Val Cys Asn Asn Gln Glu Gln Leu Leu Glu Ala Leu Arg Gln Ala 755 760 765 Val Gln Arg Arg Arg Gln Arg Arg Pro His 770 775 2699 base pairs nucleic acid double linear cDNA not provided 3 TCTAGAGAAT TCACCACCAT GGACTACAAG GACGACGATG ACAAGTCATT TATAGATCCT 60 TACCAGCACA TTATAGCAGA GGTGTCCAGG ACCTGCCTGC TCACGGTTCG TGTCCTGCAG 120 GCCCATCGCC TACCCTCTAA GGACCTAGTG ACCCCCTCTG ACTGCTACGT GACTCTCTGG 180 CTGCCCACGG CCTGCAGCCA CAGGCTCCAG ACACGCACGG TCAAGAACAG CAGTAGCCCT 240 GTCTGGAACC AGAGCTTTCA CTTCAGGATC CACAGGCAGC TCAAGAATGT CATGGAACTG 300 AAAGTCTTTG ACCAGGACCT GGTGACCGGA GATGACCCTG TGTTGTCAGT ACTGTTTGAT 360 GCGGGGACTC TGCGGGCTGG GGAGTTCCGG CGCGAGAGCT TCTCACTGAG CCCTCAGGGT 420 GAGGGGCGCC TGGAAGTTGA ATTTCGCCTG CAGAGTCTGG CTGACCGTGG CGAGTGGCTC 480 GTCAGCAATG GCGTTCTGGT GGCCCGGGAG CTCTCCTGCT TGCACGTTCA ACTGGAGGAG 540 ACAGGAGACC AGAAGTCCTC AGAGCACAGA GTTCAGCTTG TGGTTCCTGG GTCCTGTGAG 600 GGTCCGCAGG AGGCCTCTGT GGGCACTGGC ACCTTCCGCT TCCACTGCCC AGCCTGCTGG 660 GAGCAGGAGC TGAGTATTCG CCTGCAGGAT GCCCCCGAGG AGCAACTAAA GGCGCCACTG 720 AGTGCCCTGC CCTCTGGTCA AGTGGTGAGG CTTGTCTTCC CCACGTCCCA GGAGCCCCTG 780 ATGAGAGTGG AGCTGAAAAA AGAAGCAGGA CTGAGGGAGC TGGCCGTGCG ACTGGGCTTC 840 GGGCCCTGTG CAGAGGAGCA GGCCTTCCTG AGCAGGAGGA AGCAGGTGGT GGCCGCGGCC 900 TTGAGGCAGG CCCTGCAGCT GGATGGAGAC CTGCAGGAGG ATGAGATCCC AGTGGTAGCT 960 ATTATGGCCA CTGGTGGTGG GATCCGGGCA ATGACTTCCC TGTATGGGCA GCTGGCTGGC 1020 CTGAAGGAGC TGGGCCTCTT GGATTGCGTC TCCTACATCA CCGGGGCCTC GGGCTCCACC 1080 TGGGCCTTGG CCAACCTTTA TGAGGACCCA GAGTGGTCTC AGAAGGACCT GGCAGGGCCC 1140 ACTGAGTTGC TGAAGACCCA GGTGACCAAG AACAAGCTGG GTGTGCTGGC CCCCAGCCAG 1200 CTGCAGCGGT ACCGGCAGGA GCTGGCCGAG CGTGCCCGCT TGGGCTACCC AAGCTGCTTC 1260 ACCAACCTGT GGGCCCTCAT CAACGAGGCG CTGCTGCATG ATGAGCCCCA TGATCACAAG 1320 CTCTCAGATC AACGGGAGGC CCTGAGTCAT GGCCAGAACC CTCTGCCCAT CTACTGTGCC 1380 CTCAACACCA AAGGGCAGAG CCTGACCACT TTTGAATTTG GGGAGTGGTG CGAGTTCTCT 1440 CCCTACGAGG TCGGCTTCCC CAAGTACGGG GCCTTCATCC CCTCTGAGCT CTTTGGCTCC 1500 GAGTTCTTTA TGGGGCAGCT GATGAAGAGG CTTCCTGAGT CCCGCATCTG CTTCTTAGAA 1560 GGTATCTGGA GCAACCTGTA TGCAGCCAAC CTCCAGGACA GCTTATACTG GGCCTCAGAG 1620 CCCAGCCAGT TCTGGGACCG CTGGGTCAGG AACCAGGCCA ACCTGGACAA GGAGCAGGTC 1680 CCCCTTCTGA AGATAGAAGA ACCACCCTCA ACAGCCGGCA GGATAGCTGA GTTTTTCACC 1740 GATCTTCTGA CGTGGCGTCC ACTGGCCCAG GCCACACATA ATTTCCTGCG TGGCCTCCAT 1800 TTCCACAAAG ACTACTTTCA GCATCCTCAC TTCTCCACAT GGAAAGCTAC CACTCTGGAT 1860 GGGCTCCCCA ACCAGCTGAC ACCCTCGGAG CCCCACCTGT GCCTGCTGGA TGTTGGCTAC 1920 CTCATCAATA CCAGCTGCCT GCCCCTCCTG CAGCCCACTC GGGACGTGGA CCTCATCCTG 1980 TCATTGGACT ACAACCTCCA CGGAGCCTTC CAGCAGTTGC AGCTCCTGGG CCGGTTCTGC 2040 CAGGAGCAGG GGATCCCGTT CCCACCCATC TCGCCCAGCC CCGAAGAGCA GCTCCAGCCT 2100 CGGGAGTGCC ACACCTTCTC CGACCCCACC TGCCCCGGAG CCCCTGCGGT GCTGCACTTT 2160 CCTCTGGTCA GCGACTCCTT CCGGGAGTAC TCGGCCCCTG GGGTCCGGCG GACACCCGAG 2220 GAGGCGGCAG CTGGGGAGGT GAACCTGTCT TCATCGGACT CTCCCTACCA CTACACGAAG 2280 GTGACCTACA GCCAGGAGGA CGTGGACAAG CTGCTGCACC TGACACATTA CAATGTCTGC 2340 AACAACCAGG AGCAGCTGCT GGAGGCTCTG CGCCAGGCAG TGCAGCGGAG GCGGCAGCGC 2400 AGGCCCCACT GATGGCCGGG GCCCCTGCCA CCCCTAACTC TCATTCATTC CCTGGCTGCT 2460 GAGTTGCAGG TGGGAACTGT CATCACGCAG TGCTTCAGAG CCTCGGGCTC AGGTGGCACT 2520 GTCCCAGGGT CCAGGCTGAG GGCTGGGAGC TCCCTTGCGC CTCAGCAGTT TGCAGTGGGG 2580 TAAGGAGGCC AAGCCCATTT GTGTAATCAC CCAAAACCCC CCGGCCTGTG CCTGTTTTCC 2640 CTTCTGCGCT ACCTTGAGTA GTTGGAGCAC TTGATACATC ACAGACTCAT ACAAATGTG 2699 797 amino acids amino acid linear protein not provided 4 Met Asp Tyr Lys Asp Asp Asp Asp Lys Ser Phe Ile Asp Pro Tyr Gln 1 5 10 15 His Ile Ile Ala Glu Val Ser Arg Thr Cys Leu Leu Thr Val Arg Val 20 25 30 Leu Gln Ala His Arg Leu Pro Ser Lys Asp Leu Val Thr Pro Ser Asp 35 40 45 Cys Tyr Val Thr Leu Trp Leu Pro Thr Ala Cys Ser His Arg Leu Gln 50 55 60 Thr Arg Thr Val Lys Asn Ser Ser Ser Pro Val Trp Asn Gln Ser Phe 65 70 75 80 His Phe Arg Ile His Arg Gln Leu Lys Asn Val Met Glu Leu Lys Val 85 90 95 Phe Asp Gln Asp Leu Val Thr Gly Asp Asp Pro Val Leu Ser Val Leu 100 105 110 Phe Asp Ala Gly Thr Leu Arg Ala Gly Glu Phe Arg Arg Glu Ser Phe 115 120 125 Ser Leu Ser Pro Gln Gly Glu Gly Arg Leu Glu Val Glu Phe Arg Leu 130 135 140 Gln Ser Leu Ala Asp Arg Gly Glu Trp Leu Val Ser Asn Gly Val Leu 145 150 155 160 Val Ala Arg Glu Leu Ser Cys Leu His Val Gln Leu Glu Glu Thr Gly 165 170 175 Asp Gln Lys Ser Ser Glu His Arg Val Gln Leu Val Val Pro Gly Ser 180 185 190 Cys Glu Gly Pro Gln Glu Ala Ser Val Gly Thr Gly Thr Phe Arg Phe 195 200 205 His Cys Pro Ala Cys Trp Glu Gln Glu Leu Ser Ile Arg Leu Gln Asp 210 215 220 Ala Pro Glu Glu Gln Leu Lys Ala Pro Leu Ser Ala Leu Pro Ser Gly 225 230 235 240 Gln Val Val Arg Leu Val Phe Pro Thr Ser Gln Glu Pro Leu Met Arg 245 250 255 Val Glu Leu Lys Lys Glu Ala Gly Leu Arg Glu Leu Ala Val Arg Leu 260 265 270 Gly Phe Gly Pro Cys Ala Glu Glu Gln Ala Phe Leu Ser Arg Arg Lys 275 280 285 Gln Val Val Ala Ala Ala Leu Arg Gln Ala Leu Gln Leu Asp Gly Asp 290 295 300 Leu Gln Glu Asp Glu Ile Pro Val Val Ala Ile Met Ala Thr Gly Gly 305 310 315 320 Gly Ile Arg Ala Met Thr Ser Leu Tyr Gly Gln Leu Ala Gly Leu Lys 325 330 335 Glu Leu Gly Leu Leu Asp Cys Val Ser Tyr Ile Thr Gly Ala Ser Gly 340 345 350 Ser Thr Trp Ala Leu Ala Asn Leu Tyr Glu Asp Pro Glu Trp Ser Gln 355 360 365 Lys Asp Leu Ala Gly Pro Thr Glu Leu Leu Lys Thr Gln Val Thr Lys 370 375 380 Asn Lys Leu Gly Val Leu Ala Pro Ser Gln Leu Gln Arg Tyr Arg Gln 385 390 395 400 Glu Leu Ala Glu Arg Ala Arg Leu Gly Tyr Pro Ser Cys Phe Thr Asn 405 410 415 Leu Trp Ala Leu Ile Asn Glu Ala Leu Leu His Asp Glu Pro His Asp 420 425 430 His Lys Leu Ser Asp Gln Arg Glu Ala Leu Ser His Gly Gln Asn Pro 435 440 445 Leu Pro Ile Tyr Cys Ala Leu Asn Thr Lys Gly Gln Ser Leu Thr Thr 450 455 460 Phe Glu Phe Gly Glu Trp Cys Glu Phe Ser Pro Tyr Glu Val Gly Phe 465 470 475 480 Pro Lys Tyr Gly Ala Phe Ile Pro Ser Glu Leu Phe Gly Ser Glu Phe 485 490 495 Phe Met Gly Gln Leu Met Lys Arg Leu Pro Glu Ser Arg Ile Cys Phe 500 505 510 Leu Glu Gly Ile Trp Ser Asn Leu Tyr Ala Ala Asn Leu Gln Asp Ser 515 520 525 Leu Tyr Trp Ala Ser Glu Pro Ser Gln Phe Trp Asp Arg Trp Val Arg 530 535 540 Asn Gln Ala Asn Leu Asp Lys Glu Gln Val Pro Leu Leu Lys Ile Glu 545 550 555 560 Glu Pro Pro Ser Thr Ala Gly Arg Ile Ala Glu Phe Phe Thr Asp Leu 565 570 575 Leu Thr Trp Arg Pro Leu Ala Gln Ala Thr His Asn Phe Leu Arg Gly 580 585 590 Leu His Phe His Lys Asp Tyr Phe Gln His Pro His Phe Ser Thr Trp 595 600 605 Lys Ala Thr Thr Leu Asp Gly Leu Pro Asn Gln Leu Thr Pro Ser Glu 610 615 620 Pro His Leu Cys Leu Leu Asp Val Gly Tyr Leu Ile Asn Thr Ser Cys 625 630 635 640 Leu Pro Leu Leu Gln Pro Thr Arg Asp Val Asp Leu Ile Leu Ser Leu 645 650 655 Asp Tyr Asn Leu His Gly Ala Phe Gln Gln Leu Gln Leu Leu Gly Arg 660 665 670 Phe Cys Gln Glu Gln Gly Ile Pro Phe Pro Pro Ile Ser Pro Ser Pro 675 680 685 Glu Glu Gln Leu Gln Pro Arg Glu Cys His Thr Phe Ser Asp Pro Thr 690 695 700 Cys Pro Gly Ala Pro Ala Val Leu His Phe Pro Leu Val Ser Asp Ser 705 710 715 720 Phe Arg Glu Tyr Ser Ala Pro Gly Val Arg Arg Thr Pro Glu Glu Ala 725 730 735 Ala Ala Gly Glu Val Asn Leu Ser Ser Ser Asp Ser Pro Tyr His Tyr 740 745 750 Thr Lys Val Thr Tyr Ser Gln Glu Asp Val Asp Lys Leu Leu His Leu 755 760 765 Thr His Tyr Asn Val Cys Asn Asn Gln Glu Gln Leu Leu Glu Ala Leu 770 775 780 Arg Gln Ala Val Gln Arg Arg Arg Gln Arg Arg Pro His 785 790 795 22 base pairs nucleic acid single linear other nucleic acid /desc = “oligonucleotide” not provided 5 CCTCCTGCAG CCCACTCGGG AC 22 22 base pairs nucleic acid single linear other nucleic acid /desc = “oligonucleotide” not provided 6 GCTGACCAGA GGAAAGTGCA GC 22 144 base pairs nucleic acid single linear other nucleic acid /desc = “oligonucleotide” not provided 7 CTAGAGAATT CACCACCATG GACTACAAGG ACGACGATGA CAAGTCATTT ATAGATCCTT 60 ACCAGCACAT TATAGCAGAG GTGTCCAGGA CCTGCCTGCT CACGGTTCGT GTCCTGCAGG 120 CCCATCGCCT ACCCTCTAAG GACC 144 142 base pairs nucleic acid single linear other nucleic acid /desc = “oligonucleotide” not provided 8 TCTTAAGTGG TGGTACCTGA TGTTCCTGCT GCTACTGTTC AGTAAATATC TAGGAATGGT 60 CGTGTAATAT CGTCTCCACA GGTCCTGGAC GGACGAGTGC CAAGCACAGG ACGTCCGGGT 120 AGCGGATGGG AGATTCCTGG AT 142 35 amino acids amino acid linear protein not provided 9 Met Asp Tyr Lys Asp Asp Asp Asp Lys Ser Phe Ile Asp Pro Tyr Gln 1 5 10 15 His Ile Ile Ala Glu Val Ser Arg Thr Cys Leu Leu Thr Val Arg Val 20 25 30 Leu Gln Ala 35 

What is claimed is:
 1. An isolated polynucleotide comprising a nucleotide sequence selected from the group consisting of: (a) the nucleotide sequence of SEQ ID NO:1; (b) a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2; (c) a nucleotide sequence encoding a fragment of the amino acid sequence of SEQ ID NO:2 having phospholipase activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine as a substrate; (d) a nucleotide sequence which hybridizes under stringent conditions of 4×SSC at 65 degrees C. with the sequence of (a), (b) or (c) which encodes a peptide having activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine; (e) the nucleotide sequence of SEQ ID NO:3; (f) a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:4; (g) a nucleotide sequence encoding a fragment of the amino acid sequence of SEQ ID NO:4 having activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine; and (h) a nucleotide sequence which hybridizes under stringent conditions of 4×SSC at 65 degrees C. with the sequence of (e), (f), or (g) which encodes a peptide having phospholipase activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine as a substrate.
 2. An expression vector comprising the polynucleotide of claim 1 and an expression control sequence.
 3. A host cell transformed with the vector of claim
 2. 4. A process for producing a phospholipase enzyme, said process comprising: (a) establishing a culture of the host cell of claim 3 in a suitable culture medium; and (b) isolating said enzyme from said culture.
 5. The polynucleotide of claim 1 comprising the nucleotide sequence of SEQ ID NO:1.
 6. The polynucleotide of claim 1 comprising a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2.
 7. The polynucleotide of claim 1 comprising the nucleotide sequence of SEQ ID NO:3.
 8. The polynucleotide of claim 1 comprising a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:4.
 9. The polynucleotide of claim 1 comprising a nucleotide sequence encoding a fragment of the amino acid sequence of SEQ ID NO:2 having phospholipase activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine as a substrate.
 10. The polynucleotide of claim 1 comprising a nucleotide sequence which hybridizes under stringent conditions of 4XSSC at 65 degrees C with the nucleotide sequence of SEQ ID NO:1, a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2, or a nucleotide sequence encoding a fragment of the amino acid sequence of SEQ ID NO:2 having phospholipase activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidycholine as a substrate, which encodes a peptide having activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine.
 11. The polynucleotide of claim 1 comprising a nucleotide sequence encoding a fragment of the amino acid sequence of SEQ ID NO:4 having activity in a mixed micelle assay with 1-palmitoyl-2-arachidonyl-phosphatidylcholine
 12. The polynucleotide of claim 1 comprising a nucleotide sequence which hybridizes under stringent conditions of 4XSSC at 65 degrees C with the nucleotide sequence of SEQ ID NO:3, a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:4, or a nucleotide sequence encoding a fragment of the amino acid sequence of SEQ ID NO:4 having activity in a mixed micelle assay with 1-palmitoyl-2-arachidonyl-phosphatidycholine which encodes a peptide having phospholipase activity in a mixed micelle assay with 1-palmitoyl-2-[¹⁴C]-arachidonyl-phosphatidylcholine as a substrate. 